There have been numerous types of ornithopters designed for use as toys. In most of these designs, the ornithopter is shaped similarly to the well-known balsa or paper toy airplanes with a drive mechanism in the form of a rubber-band driven conventional propeller. In general, these devices do not function as a true ornithopter. One deviation from this general design was a development by William Lux, U.S. Pat. No. 3,858,350 which discloses an aerial toy intended to simulate a bird in flight. This aerial toy includes a body with relatively loose wings capable of fluttering within limits during flight, and being propelled by a “single-bladed propeller extending from only one side of the axis of rotation to cause the toy to fly along a sinuous path and induce fluttering of said wings.” Lux's device utilizing a single-bladed propeller, however, is deficient since actual test models made of that device appeared not to function in the manner described in that patent. More particularly, the device does not seem to generate forward thrust.
The Lux propeller purports to function as part of a conventional propeller by moving air rearwardly over the wings. Applicant has discovered, however, that the use of this single half-blade propeller is defective and does not provide the necessary forward thrust in combination with wing action desired in the flight of a bird. In fact, in the actual experimentations, little or no flight of this particular device was observed.
One deficiency believed to be present in the Lux device is the use therein of the single half-blade propeller. This propeller functions conventionally as a mover of air. Indeed, Lux describes the propeller blade as “preferably of the nature of a sheet of paper of such stiffness that it is normally self-sustaining.” Lux further describes the function of the blade 18. More specifically, it states that “the air resistance to movement of the blade will cause a reaction tending to push the frame and wing downwardly and tending to cause rotation of the frame in a counter-clockwise direction.” Lux thereafter describes the presumed interaction of that movement with the interaction of the wing movement to cause flopping or fluttering as the half blade propeller rotates.
Experimentation suggests that the Applicant's invention functions differently and in a superior fashion. Indeed, the Lux device made in accordance with the disclosure at best functions as a bird with a broken wing tumbling to earth without providing a true simulation of bird flight. In this device, the single half-blade propeller tends to react by flipping the wing upside down. The Lux device is accordingly a propeller-driven device in which flutter and whatever movement occurs is a result of reaction between the air resistance to movement of the propeller airfoil and the opposing resistance to air of the wings. The effectiveness in flight of the Lux half propeller is canceled or dampened by the air resistance of the half propeller itself. While it appears that the Lux device will provide a fluttering type of toy, there is no evidence it discloses a device that will move air in a fashion to cause the toy to fly forwardly.
This contrasts with the present invention which is designed to both provide a fluttering appearance and forward movement achieved by using a non air-moving pendulum-like actuating member characterized by a mass at the end of an elongated member and not by a rotatable airfoil in the form of a half propeller.
It is accordingly an objective of the present invention to provide a toy having the ability to simulate the flight of a bird including both flutter and sustained flight over a distance of many feet depending in part upon the amount of propulsion power designed for the particular unit. A further object of the present invention is to provide an ornithopter utilizing a rotatable mass in combination with moveable airfoils as a driving force rather than a propeller-driven system.
The ornithopter is further characterized by an adjustable rudder and tail assembly that may be appropriately adjusted to permit modifications of the movement of the ornithopter in flight.
A further object of the present invention is to provide an improved ornithopter which is inexpensive and easy to manufacture and which can be fabricated and sold at a comparatively low cost.
A further object of the present invention is to provide an ornithopter that can be designed in a variety of shapes to adapt to market conditions in which various bird designs may be employed.